spectrum sensing in fading channels_naveen1

8/19/2019 Spectrum Sensing in Fading Channels_naveen1

1/37

SPECTRUM SENSINGIN FADING

CHANNELSBY

B Naveen Kumar

SC14M075

Under The Guidance Of

Chris Prema


2/37

OUTLINE ha! is !he C"#ni!ive $adi"%

ha! is !he need "f c"#ni!ive radi"%

S&ec!rum sensin# me!h"ds

'i(!er )an*s

S&ec!rum sensin# in +GN Channe(


3/37

COGNITIVE RADIO,efini!i"n-

.n!e((i#en! radi"

Pr"#ramma)(e

C"nfi#ured d/namica((/ $adi" au!"ma!ica((/ de!ec!s avai(a)(e channe(s

S"me *e/"rds-

PU- &rimar/ user2(icensed user3

SU- sec"ndar/ user2un(icensed user3

'B- fi(!er )an*

C$- c"#ni!ive radi"


4/37

WHAT IS NEED OF CR? fficien! u!i(ia!i"n "f radi" s&ec!rum

O&en s&ec!rum sharin#


5/37

MAIN FUNCTIONS S&ec!rum sensin#-

,e!ec!in# unused s&ec!rum and sharin# i!6 i!h"u!

harmfu( in!erference !" "!her users

S&ec!rum Sharin#-

S&ec!rum dis!ri)u!e fair(/ am"n# SU and PU S&ec!rum M")i(i!/-

Si!chin# !he SU fr"m "ne freuenc/ )and !" an"!her

)and

S&ec!rum mana#emen!-.! is !" &redic! h" ("n# s&ec!rum h"(es are (i*e(/ remain

avai(a)(e f"r use "f SU


6/37

SPECTRUM SENSING TECHNIQUES

S&ec!rumsensin#

N"nc""&era!ive

s/s!em

ner#/ )asedsensin#

Ma!ched fi(!er)ased

de!ec!i"n

C/c("s!a!i"nar/)ased

de!ec!i"n

C""&era!ives/s!ems

.n!erference)ased sensin#


7/37

ENERGY BASED DETECTION N"nc"heren! de!ec!i"n me!h"d

B(ind si#na( de!ec!"r )ecause i! i#n"res !he s!ruc!ure "f !he si#na(

+dvan!a#es- Sim&(ici!/

N" reuiremen! "f &ri"r *n"(ed#e PU

,isadvan!a#es- ,e!ec!i"n &erf"rmance is &""r under !he (" SN$ c"ndi!i"ns8 Sensin# !ime !a*en !" achieve a #iven &r")a)i(i!/ "f de!ec!i"n

ma/ )e hi#h8

, cann"! )e used !" de!ec! s&read s&ec!rum si#na(s8


8/37

ha! is ide )and and Mu(!i Band%


9/37

OBJECTIVE$' fr"n! end

T0

Tm

TM1

902*3

9m2*3

9M12*3

'i(!er )an*

,"nc"nver!er

S:P

+:,

2

1

1∑=

k

ik

2

1

1∑=

k

ik

2

1

1∑=

k

ik

0λ

mλ

1− M λ


10/37

FILTERPr"!"!/&e fi(!er- .! is a )asic (" &ass fi(!er hich is used !"

c"ns!ruc! !he remainin# fi(!ers

Pr"(a!e fi(!er- Pr"(a!e seuence is a rea( seuence "f fini!e (en#!hN;1 and uni! ener#/ i!h !he ener#/ in !he side (")e re#i"n is

minimied8

.! is an "&!ima( ind"8 O&!ima(i!/ in !he sense "f ma


11/37

PROLATE VS KAISER

π σ 1.0=

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

Normalized frequency(w/pi)

m a g n i t u d e ( d B )

prolate

kaiser


12/37


13/37

UNIFORM FILTER BANK Ma#ni!ude res&"nses "f M fi(!ers are unif"rm(/ shif!ed

versi"n "f !he &r"!"!/&e fi(!er6 !he fi(!er )an* ")!ained is

ca((ed a )n#f*%+ f#$e% &an'

=e! @02A3 re&resen! a causa( (" &ass di#i!a( fi(!er i!h area( im&u(se res&"nse

∑∞

−∞=

−=n

n Z nh z H )()( 00


14/37

UNIFORM FILTER BANK N"6 c"nsider !he !ransfer func!i"n h"se im&u(se

res&"nse is #iven )/

here e have used !he n"!a!i"nThus6

i8e86

!he freuenc/ res&"nse "f is ")!ained )/ shif!in# !he

res&"nse "f !" !he ri#h! )/ an am"un! πk:M

,][][][ 0/2

0kn

M M nk j

k W nhenhnh −π == 10 −≤≤ M k

( ) ,][][)( 0∑∑ ∞

−∞=−∞

−∞= − ==

n

nk M n

nk k zW nh z nh z H 10 −≤≤ M k

),()( 0k M k zW H z H = 10 −≤≤ M k

)( z H k

)(0 z H

)( z H k ][nhk


15/37

UNIFORM FILTER BANK

P"(/&hase im&(emen!a!i"n-

=e! !he &r"!"!/&e (" &ass !ransfer func!i"n )e

re&resen!ed in i!s M)and &"(/&hase f"rm

here is !he !h &"(/&hase c"m&"nen!

Su)s!i!u!in# A i!h in !he e


16/37

UNIFORM FILTER BANK The a)"ve eua!i"n can )e e


17/37

UNIFORM FILTER BANK +n efficien! im&(emen!a!i"n "f M)and unif"rm s/n!hesis

fi(!er )an* as sh"n )e(" fi#

'"r e


18/37

FADING CHANNELS 'adin#- Si#na( am&(i!ude a!!enua!i"n "ver a cer!ain

&r"&a#a!i"n media8

'adin# Channe(- i! is a c"mmunica!i"n channe( !ha!e


19/37

AWGN CHANNEL The s/s!em m"de( is #iven )/

2n3 @0

r2n3D

hE


20/37

ALGORITHM

'"rm !he &r")a)i(i!/ densi!/ func!i"ns f"r @0 and @18

Ca(cu(a!e !he &r")a)i(i!/ "f fa(se a(arm )/ usin# !he @0

@/&"!hesis8

'ind !he Thresh"(d i!h !he he(& "f &r")a)i(i!/ "f fa(se a(arm8

Ca(cu(a!e &r")a)i(i!/ "f de!ec!i"n )/ usin# @1 @/&"!hesis8

Ca(cu(a!e !he P, in !erms "f !hresh"(d8


21/37

AWGN CHANNEL The e=)

2(

)2

,2

(

)0,Pr( N

N

H y P fa

Γ

Γ =>=

λ

λ

(.)uQ (.)Γ

dt t

xQ

where

N

N Q P

N

N Q P

N N N

N N N

H

H V

x

n

n D

n

n fa

nn

nn

)2

exp(2

1)(

))21(2

)1((

)

2

(

))21(2),1((

)2,(

:

:~

2

2

2

2

2

42

42

1

0

∫ ∞

−=

+

+−=

−=

++

π

σ γ

γ σ λ

σ

σ λ

γ σ γ σ

σ σ


22/37

ADAPTIVE THRESHOLD !he &r")a)i(i!/ "f err"r

+da&!ive Thresh"(d-

Dar# min2 3

)()()( λ λ λ md f e p P p +=

*λ )(λ e P

Saman +!a&a!!u6 Chin!ha Te((am)ura6 and @ai ian#8 S&ec!rum Sensin# via ner#/ ,e!ec!"r in =" SN$6 . .CC 0118


23/37

FADING MODELSRa!e#,( fa-#n, .(anne: Pr")a)i(i!/ densi!/ func!i"n

here is a SN$

The dis!ri)u!i"n ")!ained fr"m here


24/37

FADING MODELSNa'a,a+# fa-#n, .(anne: &r")a)i(i!/ densi!/ func!i"n

here m is a Na*a#ami &arame!er hen mD1 !he Na*a#ami fadin# channe( is eua( !" $a/(ei#h

fadin# channe(

The avera#e &r")a)i(i!/ de!ec!i"n "f Na*a#ami channe( is

#iven )/

here '128 6 8 H 83 is a c"nf(uen! h/&er #e"me!r/ func!i"n

mm mm

m P )()exp(

)(

1)( 1

γ γ γ

γ γ

−−Γ

= 0≥γ

Nak D P ,

))](5.0;1,()!(2)5.0([)(

2)(1 1

1

1

11

,

mnm

n!m

m P

u

n

nm

m Nak D

+++

Γ = ∑

−

=−

γ γ λ λ β

γ

)2

(

)2

)((λ

γ

γ β

−

+Γ = e

mm

m),(1 2

inf

0

12

2

λ ϕ γ γ Qe!

mx

m

−

−∫ =


25/37

WORK TO BE DONE +da&!ive Thresh"(d f"r a(( 'adin# m"de(s )/ usin# 'B8

N"ise variance ca(cu(a!i"n f"r !hresh"(ds in s&ec!rum de!ec!i"n8


26/37

REFERENCE

@aiIian Ahan#6 ,ider =e $u/e!6 ,anie( $"viras and @"n# Sun8 P"(/&hasefi(!er )an* )ased mu(!i)and s&ec!rum sensin# in c"#ni!ive radi"

s/s!ems8 .n!erna!i"na( I"urna( "f c"mmunica!i"n s/s!ems0148

'ade( '8 ,i#ham, Mohamed-Slim Alouini, and Marvin K. Simon. On !he

ner#/ ,e!ec!i"n "f Un*n"n Si#na(s "ver 'adin# Channe(s .

T$+NS+CT.ONS ON COMMUN.C+T.ONS6 0078

Saman +!a&a!!u6 Chin!ha Te((am)ura6 and @ai ian#8 S&ec!rum Sensin#via ner#/ ,e!ec!"r in =" SN$6 . .CC 0118

S!even M8Ka/8 'undamen!a(s "f S!a!is!ica( si#na( &r"cessin# ,e!ec!i"n

!he"r/

aid/ana!han8 Mu(!ira!e S/s!ems and 'i(!er Ban*s8

Yifei @uan#6 9ia"Iin# @uan#8 O&!ima( s&ec!rum sensin# "ver a mu(!i&a!h

channe(8 . .CC 01 C"#ni!ive $adi" and Ne!"r*s S/m&"sium8

Behr"u 'arhan#B"r"uIen/6 Seni"r Mem)er6 .8 'i(!er Ban* S&ec!rum

Sensin# f"r C"#ni!ive $adi"s8 . T$+NS+CT.ONS ON S.GN+=

P$OCSS.NG6 M+Y 00J8

"hn G Pr"a*is8 ,i#i!a( C"mmunica!i"ns6 '"ur!h di!i"n8


27/37


28/37


29/37

DERIVATION FOR PD AND PFAAWGN CHANNEL

Pr")a)i(i!/ Of 'a(se +(arm Pr")a)i(i!/ Of ,e!ec!i"n

+cc"rdin# !" Marcum Ffunc!i"n

here

inc"m&(e!e #amma

func!i"n

)(

)2

,(

)(

1

2/

)(2

1

)(}{

2

21

1

2

1

2/1

10

2

2

0

k

k

P

dt et k

P

vt

su#stitute

evk

dvv f H

V P P

n fa

v

t k

fa

n

v

vk

k N

n

v H

v fa

n

n

Γ

Γ =

Γ =

=

Γ =

=>=

∫

∫

∫

∞

=

−−

∞

=

−−

∞

=

σ λ

σ

σ

λ

σ λ

λ

σ

λ

dvvN

" e N

v P

dvv f H

V P P

n

s

k

v N k

sv n

d

v H

vd

n

s

)()(2

1

)(}{

2

2

1

)2

(

2

1

2

1

2

1 11

2

2

σ

σ

σ σ

λ

σ

σ

λ

λ

−

+−−∞

=

∞

=

∫

∫

=

=>=

),(

,

)()(),(

2

2

2

2

1

1

)2

(1

22

n

k D

n

s

n

v

k

x

m

m

N Q P

$#tain

N

%et

v x

put

dx x " e x

xQ

σ

λ γ

σ σ α

σ

α α

β α β

α

=

=

=

= ∫ ∞

=

−

+−

−

dt et sa t

s

a −∞

−

∫ =Γ 1

),(


30/37

DERIVATION FOR PD AND PFAAWGN CHANNEL

The Marcum Ffunc!i"n is difficu(! !" ca(cu(a!e i!s inverse

+cc"rdin# !" cen!ra( (imi! !he"rem

+&&r"


31/37

i!h a cen!ra( chisuare dis!ri)u!i"n i!h Nde#rees "f freed"m8

O!herise6 a N"n cen!ra( chisuare dis!ri)u!i"n i!h

as n"n cen!ra( &arame!er8 here is SN$ "f !he received si#na(8

+ssume !ha! @02A3 has i!s &ass )and ed#e and s!"& )and ed#e

ar"und π:M6 here M is s"me ar)i!rar/ in!e#er6 as indica!ed )e("

ωπ0 π pω sω

M

π

pω sω

γ N

γ


32/37

MULTI/BAND SPECTRUMSENSING BLOCK DIAGRAM

$' fr"n! end

T0

Tm

TM1

902*3

9m2*3

9M12*3

''T

@0

@m

@M10 )1( −− M

Z

m Z

−

,"nc"nver!er

S:P

+:,

2

1

1∑=

k

ik

2

1

1∑=

k

ik

2

1

1∑=

k

ik

0λ

mλ

1− M λ


33/37


S0e.$%)+ "en"#n, .an &e .a""#f#e- &a"e- *n:

18S&ec!rum sensin# f"r s&ec!rum "&&"r!uni!ies

a3 Primar/ !ransmissi"n de!ec!i"n

)3 C""&era!ive and c"((a)"ra!ive de!ec!i"n

8 S&ec!rum sensin# f"r in!erference de!ec!i"n

c3 .n!erference !em&era!ure de!ec!i"n

d3Primar/ receiver de!ec!i"n

a1P%#+a%! $%an"+#""#*n -e$e.$#*n:The de!ec!i"n "f &rimar/ users is iden!ified )ased "n !he receivedsi#na( a! !he C$8

a3 ner#/ )ased de!ec!i"n

)3 Ma!ched fi(!er de!ec!i"n

c3 C/c("s!a!i"nar/ )ased de!ec!i"n


34/37


&1 C**0e%a$#2e an- .*a&*%a$#2e -e$e.$#*n:PU de!ec!ed re(ia)(/ )/ in!erac!in# "r c""&era!in# i!h

"!her users me!h"d cen!ra(ied access !" s&ec!rum

c""rdina!ed )/ a s&ec!rum server "r dis!ri)u!ed

a&&r"ach im&(ied )/ !he s&ec!rum ("ad sm""!hin#a(#"ri!hm "r e

receiverLs ("ca( "sci((a!"r (ea*a#e &"er


35/37

MATCHED FILTER .! is a (inear fi(!er desi#ned !" ma


36/37

CYCLOSTATIONARY FEATUREDETECTION

C/c("s!a!i"nar/ fea!ure de!ec!i"n is a me!h"d f"r de!ec!in# &rimar/

user !ransmissi"ns )/ e


37/37

Under (" SN$ c"ndi!i"n

D

Bu! hi#h SN$ c"ndi!i"n

*λ 2σ N

spectrum sensing in fading channels_naveen1

Documents